They're awesome! I like to think of them as being as close as you can get to how Danmaku fights in Gensokyo actually look like. Ocean Of Lazers is how i'd describe it.
Not really a fan of "Humans Vs. Yukari", however, its not bad, its just kind of weak compared to the others in my opinion because of the anti-climatic ending. Also Sakuya's knife orb things were weird. Thankfully, Marisa vs Okuu made for it in spades. I'm looking forward to the Koishi fight.
I also recommend ImpluseJP's
"Touhou Dogfight" (Which made before MinusT's videos) as another cool 3d animation of a Touhou boss fight. It's just as awesome as Minus', aside from the models and graphics looking like an late PS1 game.
............Now i kinda wanna play a 3d Touhou game on the Playstation.
(Wait, shouldn't this be in the Recovery Center section?)